Finding the Fourth Proportional to 1,014.32, 1,399.86 and 621.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,014.32 : 1,399.86 = 621.60 : x
2. Step 2: Convert to fraction form
   1,014.32/1,399.86 = 621.60/x
3. Step 3: Cross multiply
   1,014.32x = 1,399.86 × 621.60
4. Step 4: Simplify right side
   1,014.32x = 870,152.98
5. Step 5: Solve for x
   x = 870,152.98/1,014.32
6. Step 6: Final answer
   x = 857.87